I have a 1972 1.7 car. The idle has been high for some time. Yesterday I was looking for a vacuum leak and discovered that the mechanics had routed a large,1/2 line into the rubber tubing between the air cleaner and throttle body that had full vacuum. When I plugged it my idle issues went away. I'm trying to get all of the hoses to their proper location but have no idea where that is. Is there a schematic that shows the routing of the vacuum and smog lines. Also which smog lines can I get rid of? Thanks

bowlsby.net

http://www.pelicanparts.com/914/technical_...el_diagrams.htm

Pelican Parts again is your friend for either system

Thanks much. Two questions arise, the line that goes into the intake boot is the one that had full vacuum running in it. It passes through a valve on top of the engine before it goes to the intake manifold. what is this valve? and if there is a vacuum leak through it is it bad? Also I have a 13mm coming out of the heads to the left of the intake attachment, is this smog? where does it go? right now there is nothing on them(either side) and I can feel a slight discharge coming out of it.

First Question: I think you might be thinking about the AAR (Auxiliary Air Regulator). This regulator controls air flow. There is a value in there and adjusts air flow. These do go bad sometimes.

Second: Not really smog. Hoses to go to inlets right above the oil dip stick.

Note: All vacuum leaks are bad! You engine will not idle at 800 rpm. Car will run rough.

That's where that hose is supposed to go, so they had it right before you started mucking about. Make sure the AAR is working.

The Cap'n

Another place for vacuum leaks are the elbows. See picture. They can crack or split.

The AAR (Auxiliary Air Regulator) is allowing full vacuum to leak out of the line going into the intake boot. I plugged the line and the car idles properly but this vale needs to be fixed or replaced I think. Is it fixable?

Remove it and soak the inside with a good penetrate. If put in the freezer, you should be able to blow thru it. Hook it up to 12 volts, positive to the wire and neg to the unit casing.
Within 5 minutes it should be warm or even hot with no air allowed thru. If it doesn't work as designed, get another one. I have a few as do most of us here. Should be able to find one close to you.

Had the same AAR problem on my 2.0 D-Jet. Looks like you found the culprit.

So if I had to guess this just increases the idle when cold?

I took off the AAR unit and found that the wire into it is broken. So I guess I'm in line to buy another one.